Did you put the AllowGuests attribute to yes in your deeplink configuration?
TL;DR: You need to add /link/ to your allowed request handlers in your project deployment tab.
By default, the cloud portal blocks incoming traffic to anything but the base URL for security reasons. As the deep link module works by catching traffic to https://<yourURL>/link/<customLink>, this functionality is automatically disabled.
You can customize your request handlers under Project home > Deploy > Production/Acceptance/Test details > Network > Request Handlers. Simply add a new handler with /link/ as the path and 'Starts with' as a match type and you should be good to go.